JP2006121536A - Antenna device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna device and its manufacturing method for making the body small without decreasing an antenna gain as much as possible and preventing moisture ingress inside the antenna device. <P>SOLUTION: A patch conductor 12 is provided on one face of a first dielectric substrate 10, and a second dielectric substrate 14 with a grounding conductor 18 is provided opposite to this face of the first dielectric substrate 10. The first dielectric substrate 10 and the second dielectric substrate 14 are separated with a prescribed space through a lower case 16 stuck to the first dielectric substrate 10. A mixed dielectric substance 30 intervenes without a gap between the first dielectric substrate 10 and the second dielectric substrate 14, and a specific inductive capacity of the mixed dielectric substance is so determined according to the area of the grounding conductor 18 that an antenna gain becomes maximum. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna device suitable for communication using a frequency of GHz, and more particularly to an antenna device applicable to a glass antenna of a vehicle.

  In recent years, in order to make a vehicle run more smoothly by performing communication using electromagnetic waves between an in-vehicle communication device and an external communication device, GPS (Satellite Positioning System: Global Positioning System), VICS (Road Traffic Information System: Vehicle Information and Communication System) and ETC (Electric Toll Collection System) are used. A receiving apparatus for receiving a satellite broadcast channel has also been put into practical use.

  As an antenna of an in-vehicle communication device used in these systems, for example, a configuration in which an antenna device including a microstrip antenna (hereinafter referred to as MSA) is attached to a front window glass plate of a vehicle is used.

For example, Patent Document 1 below also discloses an improved technique for a microstrip antenna.
JP 2002-246817 A

  However, in the above conventional technique, a technique for reducing the size of the antenna device without losing the gain (antenna gain) as much as possible has not been disclosed, and it has been difficult to meet the demand for size reduction. In addition, when the antenna device is installed inside a window glass and used as an antenna for an in-vehicle communication device, the inside of the vehicle is likely to become highly humid when a person rides on it, thus preventing moisture from entering the antenna device. Although it is necessary, in the above-described prior art, measures for preventing moisture penetration were insufficient.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an antenna device that can be miniaturized without losing the antenna gain as much as possible and can prevent moisture from entering the antenna device, and a method for manufacturing the antenna device. Is to provide.

  In order to achieve the above object, the present invention provides an antenna device, comprising a first dielectric substrate, a patch conductor provided on one surface of the first dielectric substrate, and the first dielectric substrate. Provided on one surface of the body substrate, a second dielectric substrate facing and spaced apart by a predetermined distance via a spacer, and a surface of the second dielectric substrate facing the patch conductor. A dielectric material A having at least temporary fluidity between the first dielectric substrate and the second dielectric substrate, and a relative dielectric constant different from that of the dielectric material A. A mixed dielectric material mixed with a dielectric material B having an intervening property is interposed, and a relative dielectric constant of the mixed dielectric material is determined according to an area of the ground conductor. Here, it is preferable that the mixed dielectric material is interposed between the first dielectric substrate and the second dielectric substrate without any gap.

  The dielectric material A is preferably silicone rubber, and the dielectric material B preferably has a relative dielectric constant greater than that of the dielectric material A. The dielectric material B is preferably in the form of particles, particularly preferably titanium oxide particles or alumina particles. Further, the dielectric substance B may be air bubbles.

  The antenna device further includes an electromagnetic coupling conductor extending from a counter substrate surface of the second dielectric substrate toward the first dielectric substrate, and the electromagnetic coupling conductor. It is preferable that the ground conductor and the ground conductor are galvanically insulated and the electromagnetic coupling conductor and the patch conductor are electromagnetically coupled.

  The antenna device protrudes from the counter substrate surface of the second dielectric substrate toward the first dielectric substrate, and is electrically connected to a patch conductor provided on the first dielectric substrate as a signal line. It is preferable that the columnar conductors are connected to each other, and the columnar conductors and the ground conductors are galvanically insulated.

  In addition, the first dielectric substrate is preferably made of glass, and particularly preferably an automotive window glass having a curved surface.

Moreover, this invention is a manufacturing method of an antenna apparatus provided with the process of (1)-(5) below, It is characterized by the above-mentioned.
(1) Prepare a window glass plate that is the first dielectric substrate that is fitted in the opening of the vehicle and provided with the patch conductor;
Alternatively, a window glass plate, which is the first dielectric substrate, is prepared before being fitted into the opening of the vehicle and provided with the patch conductor.
(2) An adhesion part is formed in a window glass plate, or an adhesion part is formed in the window glass plate side surface of the said spacer.
(3) A spacer is attached to a predetermined portion of the window glass plate through the bonding portion.
(4) After the second dielectric substrate is fixed to the spacer, the mixed dielectric material is injected into a gap surrounded by the window glass plate, the second dielectric substrate, and the spacer.
(5) In the above step (1), when the window glass plate before being fitted into the opening of the vehicle is used, the window glass plate is fitted into the opening of the vehicle.

  Further, in the manufacturing method of the antenna device, instead of the step (4), a molding frame is provided on the second dielectric substrate, and the mixed dielectric substance is caused to flow into the frame to be fluid. After lowering, the step of removing the frame and fixing the second dielectric substrate to the spacer may be provided.

  Here, in the step (4) or the step provided in place of the step (4), it is preferable that the electromagnetic coupling conductor or the columnar conductor is attached to the second dielectric substrate. is there.

  According to the present invention, the antenna device can be configured so as not to impair the antenna gain as much as possible by determining the relative dielectric constant of the mixed dielectric material according to the area of the ground conductor. Further, since the mixed dielectric substance can be interposed between the first dielectric substrate and the second dielectric substrate without any gap, moisture intrusion can be prevented.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of the antenna device of the present invention. FIG. 2 is a schematic conceptual diagram of main components of the antenna device, and the cross-sectional view shown in FIG. 1 is a cross-sectional view taken along line A-A ′ shown in FIG. 2.

  1 and 2, a patch conductor 12 is provided on one surface of the first dielectric substrate 10. In addition, a second dielectric substrate 14 is disposed opposite to one surface of the first dielectric substrate 10, and the first dielectric substrate 10 and the second dielectric substrate 14 are spacers. They are separated at a predetermined interval via a certain lower case 16. A ground conductor 18 is provided on the surface of the second dielectric substrate 14 facing the patch conductor 12 (hereinafter referred to as the counter substrate surface).

  Further, in the present embodiment, the electromagnetic coupling conductor 20 is provided extending from the counter substrate surface toward the first dielectric substrate 10 side, and the electromagnetic coupling conductor 20 and the patch conductor 12 are provided. It is electromagnetically coupled. The electromagnetic coupling conductor 20 is galvanically insulated from the ground conductor 18.

  The lower case 16, which is a spacer, is bonded and fixed to the first dielectric substrate 10 by an adhesive portion 22, and the upper lid case 24 is locked to the lower case 16 and the first dielectric substrate 10 is fixed. It is attached. As a result, the upper lid case 24 is fixed at a predetermined position of the first dielectric substrate 10, the electromagnetic coupling conductor 20 is disposed at a predetermined position, and the lower case 16 as a spacer allows the second dielectric material An antenna device having an MSA antenna in which the substrate 14 and the first dielectric substrate 10 are separated by a predetermined interval is assembled. The use of the spacer in this way is easy to produce with a simple structure when the distance between the first dielectric substrate 10 and the second dielectric substrate 14 is several mm or more in order to improve the antenna gain. Because it can. Further, when a window glass plate for a vehicle is used as the first dielectric substrate 10, since this window glass plate usually has a curvature, the curvature is absorbed by the spacer and the second glass plate is secondly formed. This is because the dielectric substrate 14 can be reliably provided. Further, if the structure is such that the second dielectric substrate 14 can be easily removed from the spacer, it is convenient for repair.

  In the example shown in FIG. 2, the shape of the patch conductor 12 provided on one surface of the first dielectric substrate 10 described above is such that a notch 12b is provided at one corner and a diagonal of a square or a substantially square. This is a hexagonal shape that is effective for circularly polarized waves. However, the present invention is not limited to this, and the shape of the patch conductor 12 may be a square such as a square or a rectangle, a polygon, a circle, an ellipse, or the like. In order to improve the circular polarization characteristic, it is preferable to provide the cutout portion 12b in the patch conductor 12 as described above. In the example illustrated in FIG. 2, the shape of the notch 12 b is a right-angled isosceles triangle or a substantially right-angled isosceles triangle, but the shape of the notch 12 b is not limited thereto. In particular, in order to obtain a patch shape effective for circularly polarized waves, a known circularly polarized patch shape in MSA, such as providing a protrusion on a part of the outer periphery of the patch or providing a slit inside the patch, etc. Can also be used.

  The electromagnetic coupling conductor 20 passes through a through hole (not shown) provided in the second dielectric substrate 14, and one end 20a of the electromagnetic coupling conductor 20 is formed on the second dielectric substrate. 14 is provided on the surface opposite to the opposing substrate surface (hereinafter referred to as a non-opposing substrate surface), and is connected to a transmission conductor 26 functioning as a signal line by soldering or the like. The electromagnetic coupling conductor 20 penetrating the through hole is extended so as to protrude from the counter substrate surface.

  In the example illustrated in FIG. 1, the electromagnetic coupling conductor 20 is once extended from the second dielectric substrate 14 toward the first dielectric substrate 10 and reaches the surface of the first dielectric substrate 10. Before being bent, it is bent or bent and extended parallel to the patch conductor 12. The extended portion is separated from the patch conductor 12 by a predetermined distance h in a direction perpendicular to the surface of the patch conductor 12. The electromagnetic coupling conductor 20 is not limited to this, and the portion of the electromagnetic coupling conductor 20 near the patch conductor 12 may not be parallel to the patch conductor 12. The electromagnetic coupling conductor 20 is made of a cylindrical conductor configured in a predetermined shape, but is not limited thereto, and may be a conductive plate-shaped body configured in a predetermined shape. As a material for such an electromagnetic coupling conductor 20, copper, tin, aluminum, iron, silver, gold, platinum, alloys thereof, or those obtained by plating the surfaces of these metals can be used.

  The transmission conductor 26 described above is connected to the core wire of the coaxial cable 28 connected to an external circuit such as an RF (Radio Frequency) circuit outside the antenna device, and the ground conductor 18 is connected to the external conductor of the coaxial cable 28. ing. The outer conductor of the coaxial cable 28 is preferably grounded.

  In the example shown in FIG. 1, as described above, the electromagnetic coupling conductor 20 is connected to the patch conductor 12 by electromagnetic coupling, and a signal from an external circuit is passed through the coaxial cable 28, the transmission conductor 26, and the like. 12, and the signal from the patch conductor 12 is transmitted to an external circuit via the transmission conductor 26 and the coaxial cable 28. The second dielectric substrate 14 is housed and supported at a predetermined position of an upper cover case 24 locked to the lower case 16, and the upper cover case 24 is configured to surround the patch conductor 12. Yes.

  In the present invention, the distance between the patch conductor 12 and the ground conductor 18 is appropriately set according to the wavelength of the electromagnetic wave used in the antenna device from the viewpoint of ensuring the transmission / reception performance of the antenna device.

  A characteristic point in FIG. 1 is that a mixed dielectric material 30 is interposed between the first dielectric substrate 10 and the second dielectric substrate 14 without a gap. The mixed dielectric material 30 is a mixture of a dielectric material A having fluidity and a dielectric material B having a relative dielectric constant different from that of the dielectric material A. As the dielectric substance A, for example, silicone rubber can be used. As the dielectric substance B, for example, titanium oxide or alumina particles, air bubbles, or the like can be used. Here, the particle size (diameter) of the dielectric material B is preferably 0.1 to 50 μm. When the particle size is 0.1 μm or more, the productivity is excellent, and when the particle size is 50 μm or less, the antenna characteristics are stable and preferable. In addition, as the dielectric material A, modified silicone rubber, urethane rubber, butyl rubber, styrene thermoplastic elastomer, polysulfide rubber, and the like can be used. When a thermoplastic resin is used, mixed dielectric is obtained by extrusion molding or injection molding. It is also possible to form the active substance 30.

  In addition, a high dielectric material such as barium titanate or strontium titanate can be used as the dielectric material B, but it is preferable that the dielectric material B has a high relative dielectric constant, a low dielectric loss, and a low cost. In particular, in automobile applications, it is desirable that the relative dielectric constant does not change greatly due to a change in the ambient temperature used in that the antenna characteristics do not change.

  The relative dielectric constant of the mixed dielectric material 30 can be controlled to an arbitrary value by adjusting the mixing ratio of the dielectric material A and the dielectric material B. As will be described later, when the antenna device is downsized and the area of the ground conductor 18 is reduced, the reduction in antenna gain can be alleviated by optimizing the relative dielectric constant of the mixed dielectric material 30. it can. That is, the relative dielectric constant of the mixed dielectric material is determined so as to maximize the antenna gain according to the area of the ground conductor 18.

  Further, since the mixed dielectric material 30 is configured by mixing the dielectric material A having fluidity with the dielectric material B, it needs to have fluidity at least temporarily. Here, “at least temporarily has fluidity” is a condition for mixing the dielectric substance B. The dielectric material B can be mixed in a state where the dielectric material A is fluidized, and the mixed dielectric material 30 can be easily mixed with the first dielectric substrate 10 and the second dielectric substrate 14. It is possible to interpose them with no gap. As the properties of such a dielectric substance A, in addition to those that always have fluidity, those that cure from a fluid state by irradiation with energy such as light and heat, those that cure by moisture, or those that have thermoplasticity, etc. There is. The mixed dielectric material 30 is preferably in the form of rubber or gel as the final properties when used in the antenna of the present invention. This is because there is a high effect of preventing moisture intrusion by interposing the first dielectric substrate 10 and the second dielectric substrate 14 without any gap. Therefore, the mixed dielectric material 30 can be interposed between the first dielectric substrate 10 and the second dielectric substrate 14 without any gap, and moisture intrusion into the antenna device can be prevented. In particular, when the first dielectric substrate 10 is a window glass plate for a vehicle, the window glass plate for a vehicle usually has a curvature, and therefore, by using the fluid mixed dielectric material 30, the gap can be uniformly formed in the gap. It becomes possible to fill and interpose. With such a configuration, when the antenna device of the present invention includes electronic components such as an amplifier, the effect of protecting them from moisture such as water droplets and moisture can be obtained, which is preferable in practice.

  FIG. 3 is a cross-sectional view showing an embodiment of the antenna device of the present invention different from the example shown in FIG. 1, and FIG. 4 is a schematic conceptual diagram of the main components of the example shown in FIG. The cross-sectional view shown in FIG. 3 is a cross-sectional view taken along the line A-A ′ shown in FIG. 4. However, the upper lid case 24 is not shown in FIG.

  3 and 4, a patch conductor 12 that is a radiation conductor is provided on one surface of the first dielectric substrate 10. In addition, a second dielectric substrate 14 is disposed opposite to one surface of the first dielectric substrate 10, and the first dielectric substrate 10 and the second dielectric substrate 14 are spacers. They are separated at a predetermined interval via a certain lower case 16. A ground conductor 18 is provided on the surface of the second dielectric substrate 14 facing the patch conductor 12 (hereinafter referred to as the counter substrate surface).

  In a part of the region where the patch conductor 12 is formed, an island-shaped conductor 32 is formed that is separated from the patch conductor 12 and surrounded by the patch conductor 12. A planar antenna element 34 that radiates electromagnetic waves is formed.

  The island-shaped conductor 32 is a connection portion of the antenna element 34 when the columnar conductor 36 is connected to the antenna element 34 as will be described later. The island-shaped conductor 32 in the antenna element 34 is not limited to a rectangular shape, and may be a circular shape, and the shape is not particularly limited.

  In the example shown in FIG. 3, the columnar conductors 36 are provided so as to protrude from the counter substrate surface. One end of the columnar conductor 36 passes through a through-hole penetrating the second dielectric substrate 14 and passes through the second dielectric substrate 14. The second dielectric substrate 14 is a non-opposite surface opposite to the counter substrate surface. It is connected to a transmission conductor 26 as a signal line provided on the substrate surface by soldering or the like, and is fixed to the second dielectric substrate 14. On the other hand, the other end of the columnar conductor 36 is in contact with the approximate center of the island-shaped conductor 32 provided on the first dielectric substrate 10. The ground conductor 18 is provided on the entire surface of the counter substrate surface of the second dielectric substrate 14 excluding the through hole drilled in the second dielectric substrate 14 and the vicinity region around the through hole. Is preferred. The columnar conductor 36 is galvanically insulated from the ground conductor 18 and protrudes from the counter substrate surface.

  As described above, the columnar conductor 36 connects the antenna element 34 and the transmission conductor 26, feeds a transmission signal from an external circuit to the patch conductor 12 at the time of transmission, and from the patch conductor 12 at the time of reception. The transmission signal is transmitted to an external circuit via the transmission conductor 26 and the coaxial cable 28, etc. The island-shaped conductor 32 is configured to be separated from the patch conductor 12 by a certain gap formed by the fact that no conductor is provided on the surface of the first dielectric substrate 10, and the periphery is surrounded by the patch conductor 12. It functions as a capacitive correction element that corrects the inductivity (inductance) of the columnar conductor 36 or the patch conductor 12. The island-like conductor 32 is adjusted so as to match, for example, 50Ω, which is a characteristic impedance usually used in a high-frequency signal line. Specifically, in consideration of the inductivity of the columnar conductor 36 and the inductivity of the patch conductor 12, the shape and size of the island-shaped conductor 32 and the width of the gap between the island-shaped conductor 32 and the patch conductor 12 are considered. Is adjusted. Thus, the columnar conductor 36 is connected to the antenna element 34 in a high-frequency circuit manner.

  When a vehicle window glass plate is used as the first dielectric substrate 10, since the vehicle window glass plate has a normal curvature, the columnar conductor 36 is caused by a difference in curvature of the individual window glass plates. However, there is a problem that it is difficult to contact the island-like conductor 32 and to be disconnected. Therefore, in such a case, it is preferable to use a spring probe as the columnar conductor 36. When a spring probe is used as the columnar conductor 36, the columnar conductor 36 can be reliably contacted and connected to the island-shaped conductor 32 without changing the design of the entire antenna device shown in FIG. Further, when a spring probe is used as the columnar conductor 36, it is possible to produce smoothly by absorbing the variation in the distortion of the window glass plate and the variation in the distortion of the second dielectric substrate 14 in mass production. In this case, the stroke of the spring probe is preferably 0.2 to 1.5 mm, particularly preferably 0.2 to 0.8 mm. Further, the pressing force of the spring probe does not damage the island-like conductor 32, and the contact portion does not vibrate due to the vibration of the vehicle such as an automobile. In consideration of the above, 0.2 to 50 N is preferable. The spring probe preferably has a low electrical resistance in order to reduce electrical loss during signal transmission.

  A characteristic point in FIG. 3 is that the mixed dielectric substance 30 is interposed between the first dielectric substrate 10 and the second dielectric substrate 14 without any gap, as in the embodiment shown in FIG. This is the point.

  FIGS. 5A and 5B are explanatory views of the shape constants a to d, g, and h of the antenna device of the type shown in FIG. Among the shape constants, a to d are parameters that define the shape of the patch conductor 12. The shape constant g is the distance between the surface of the patch conductor 12 and the electromagnetic coupling conductor 20, and the shape constant h is the thickness of the mixed dielectric material 30.

  Table 1 shows the antenna gain for a left-handed circularly polarized wave having a frequency of 2.338 GHz for each size (area) of the ground conductor 18 and relative permittivity of the mixed dielectric material 30 using the shape constant. The calculated simulation result is shown. Each shape constant shown in Table 1 is a value that maximizes the left-handed circularly polarized antenna gain with respect to the size of each grounding conductor 18 and the relative dielectric constant of the mixed dielectric material 30.

  6 shows the relationship between the relative permittivity of the mixed dielectric material 30 and the left-handed circularly polarized antenna gain for each size of the ground conductor 18 based on the results of Table 1 above.

  As can be seen from Table 1 and FIG. 6, when the size of the ground conductor 18 is 80 × 80 mm, the antenna gain is a maximum value of 7.1 dBic when the relative dielectric constant of the mixed dielectric material 30 is 1.0. It becomes. Similarly, when the size of the grounding conductor 18 is 60 × 60 mm, the antenna gain becomes a maximum value of 5.0 dBic when the relative dielectric constant of the mixed dielectric material 30 is 2.7. When the relative dielectric constant of the mixed dielectric material 30 is 4.0, the maximum antenna gain is 3.0 dBic, and when the size of the ground conductor 18 is 30 × 30 mm. When the relative dielectric constant of the mixed dielectric material 30 is 7.0, the maximum antenna gain is 1.2 dBic. However, the maximum value of the antenna gain decreases as 7.1 dBic → 5.0 dBic → 3.0 dBic → 1.2 dBic as the size of the ground conductor 18 is gradually reduced from 80 × 80 mm to 30 × 30 mm.

  From the above results, when the size of the ground conductor 18 is reduced in order to reduce the size of the antenna device, the antenna gain also decreases, but the relative dielectric constant of the mixed dielectric material 30 is reduced to the size of the ground conductor 18 ( If it is appropriately determined according to (area), the maximum antenna gain in the size of the ground conductor 18 can be obtained. Thereby, it is possible to mitigate a decrease in antenna gain due to downsizing of the antenna device.

  As described above, silicone rubber or the like is used for the dielectric material A constituting the mixed dielectric material 30, and the relative dielectric constant of the silicone rubber is usually 2.3 to 4.3. Therefore, in order to adjust the relative dielectric constant of the mixed dielectric material 30 to the desired value, the dielectric material B having a relative dielectric constant different from that of the dielectric material A is mixed with the dielectric material A. . For example, in order to make the relative dielectric constant of the mixed dielectric material 30 smaller than the relative dielectric constant of silicone rubber as the dielectric material A, air bubbles are mixed into the silicone rubber. However, since the relative dielectric constant of air is 1.0, the relative dielectric constant of the mixed dielectric material 30 cannot be lowered to 1.0. Therefore, when the size of the ground conductor 18 is 80 × 80 mm, the antenna gain cannot be maximized when the mixed dielectric material 30 is used. In this case, the effect of preventing moisture intrusion into the antenna device and the effect of improving the antenna gain that cannot be obtained when air is used between the first dielectric substrate 10 and the second dielectric substrate 14. In consideration of the above, the dielectric constant of the mixed dielectric material 30 is configured to be as low as possible due to air bubbles.

  In order to make the relative dielectric constant of the mixed dielectric material 30 larger than that of the silicone rubber as the dielectric material A, the ratio of the dielectric material A such as rutile titanium oxide or alumina particles to the silicone rubber A dielectric material B having a relative dielectric constant larger than the dielectric constant is mixed. Since the relative dielectric constant of rutile titanium oxide is 80 to 100 and the relative dielectric constant of alumina is about 8 to 10, the relative dielectric constant of the mixed dielectric material 30 can be increased by mixing an appropriate amount with silicone rubber. It can be adjusted to a desired value.

  The examples shown in FIGS. 5 and 6 and Table 1 are simulations for the antenna device of the type shown in FIG. 1, but similar results are obtained for the antenna device of the type shown in FIG.

  Next, an example of a method for manufacturing the antenna device according to the present invention will be described. 7A to 7D are cross-sectional views for explaining the manufacturing process of the antenna device. In FIG. 7A, first, the first dielectric substrate 10 is prepared. As the first dielectric substrate 10, a vehicle window glass plate is used. This window glass plate may be in a state of being fitted in the opening of the vehicle or in a state before being fitted. A patch conductor 12 is provided in advance on the window glass plate. In the case of the antenna device of the type shown in FIG. 3, an island-shaped conductor 32 is also provided.

  Next, in FIG.7 (b), the adhesion part 22 is formed in the surface at the side of the window glass plate of the lower case 16 which is a spacer. The bonding part 22 can be formed, for example, by applying an adhesive to the surface of the lower case 16. The bonding portion 22 may be formed on the window glass plate side.

  Next, in FIG. 7C, the lower case 16 is attached to a predetermined portion of the window glass plate as the first dielectric substrate 10 through the bonding portion 22.

  Further, in FIG. 7D, after fixing the second dielectric substrate 14 to the lower case 16, a window glass plate as the first dielectric substrate 10, the second dielectric substrate 14, the lower case 16, The mixed dielectric material 30 is injected into the gap surrounded by. The mixed dielectric material 30 is preferably injected from an appropriate injection hole (not shown) formed in the lower case 16 or the second dielectric substrate 14. The injected mixed dielectric material 30 may be made into a gel or rubber shape by reducing the fluidity by heating or adding a cross-linking material.

  Further, the grounding conductor 18, the electromagnetic coupling conductor 20 or the columnar conductor 36, the transmission conductor 26, and the coaxial cable 28 are provided on the second dielectric substrate 14 before being fixed to the lower case 16. In the example shown in FIG. 7D, an electromagnetic coupling conductor 20 is provided.

  Thereafter, the upper lid case 24 (not shown) is locked to the lower case 16. In FIG. 7A, when a window glass plate before being fitted into the opening of the vehicle is used as the first dielectric substrate 10, the window glass plate is fitted into the opening of the vehicle.

  FIGS. 8A to 8C show an example of a forming method instead of the step of injecting the mixed dielectric material 30 shown in FIG. 7D. In FIG. 8A, a forming frame 38 is provided on the second dielectric substrate 14 provided with the ground conductor 18 and the electromagnetic coupling conductor 20 (or the columnar conductor 36).

  Next, in FIG. 8B, the mixed dielectric material 30 is caused to flow into the frame 38. Thereafter, the mixed dielectric material 30 is reduced in fluidity by heating, addition of a crosslinking material, or the like to form a gel or rubber.

  Further, in FIG. 8C, the frame 38 is removed, and the second dielectric substrate 14 is fixed to the lower case 16 that has been attached to the first dielectric substrate 10 in advance.

  7 and 8, the mixed dielectric material 30 can be interposed between the first dielectric substrate 10 and the second dielectric substrate 14 without a gap.

  As an embodiment of the present invention, an example in which the relative dielectric constant of the mixed dielectric material 30 is adjusted by mixing silicone rubber as the dielectric material A and titanium oxide or alumina particles as the dielectric material B will be described. In addition, this invention is not limited to these Examples, Various improvement and change are also included in this invention, unless the summary of this invention is impaired.

In this example, a dielectric material A and a dielectric material B described below were mixed to produce a mixed dielectric material, and the relative dielectric constant was measured.
-Dielectric material A: SE1858 manufactured by Dow Corning Torre Silicone Co., 2.7
Dielectric substance B1 (titanium oxide): manufactured by Kanto Chemical Co., Inc. Titanium oxide (IV), rutile type particle size 0.1 to 0.3 μm
Dielectric material B2 (alumina): Sumitomo Random, manufactured by Sumitomo Chemical Co., Ltd., particle size 2 μm

  The above dielectric material A and dielectric material B were mixed in the proportions shown in Table 2.

  Table 2 also shows the measurement results of the relative dielectric constant of each mixed dielectric substance at 2.356 GHz. The relative dielectric constant was measured using an HP85070A dielectric probe manufactured by Agilent Technologies.

  FIG. 9 shows the relative dielectric constant of a mixed dielectric material obtained by mixing titanium oxide with SE1885 among the measurement results shown in Table 2, and FIG. 10 shows the measurement results shown in Table 2. The relative dielectric constant of a mixed dielectric material obtained by mixing SE1885 with alumina, where the vertical axis indicates the relative dielectric constant and the horizontal axis indicates the concentration (weight percent) of titanium oxide or alumina.

  As shown in Table 2 and FIGS. 9 and 10, the relative dielectric constant of the mixed dielectric material can be changed by mixing an appropriate amount of titanium oxide or alumina with silicone. In particular, when titanium oxide is used, the relative dielectric constant of the mixed dielectric material can be changed in the range of 3.0 to 11.4, and the simulation results shown in Table 1 described above can be realized. It becomes possible.

It is sectional drawing which shows one Embodiment of the antenna device of this invention. It is a schematic conceptual diagram of the main components of the antenna device shown in FIG. It is sectional drawing which shows other embodiment of the antenna apparatus of this invention. It is a schematic conceptual diagram of the main components of the antenna device shown in FIG. It is explanatory drawing of the shape constant of the antenna apparatus of the format shown by FIG. It is explanatory drawing of the relationship between the dielectric constant of a mixed dielectric material, and the antenna gain of a left-handed circularly polarized wave. It is sectional drawing for demonstrating the manufacturing process of the antenna device of this invention. It is a figure which shows the example of the formation method of a mixed dielectric material. It is a figure which shows the dielectric constant of the mixed dielectric material which mixed the titanium oxide with the silicone. It is a figure which shows the dielectric constant of the mixed dielectric material which mixed the alumina with the silicone.

Explanation of symbols

  10 First dielectric substrate, 12 Patch conductor, 14 Second dielectric substrate, 16 Lower case, 18 Ground conductor, 20 Electromagnetic coupling conductor, 22 Adhering portion, 24 Upper lid case, 26 Transmission conductor, 28 Coaxial cable, 30 mixed dielectric material, 32 island conductor, 34 antenna element, 36 columnar conductor, 38 frame.

Claims (14)

A first dielectric substrate;
A patch conductor provided on one surface of the first dielectric substrate;
One surface of the first dielectric substrate, a second dielectric substrate disposed opposite to the first dielectric substrate with a predetermined spacing therebetween via a spacer;
A ground conductor provided on an opposing substrate surface facing the patch conductor of the second dielectric substrate;
With
Between the first dielectric substrate and the second dielectric substrate, a dielectric material A having fluidity at least temporarily and a dielectric material B having a relative dielectric constant different from that of the dielectric material A And a mixed dielectric material mixed therewith, and the relative dielectric constant of the mixed dielectric material is determined according to the area of the ground conductor.   2. The antenna device according to claim 1, wherein the mixed dielectric substance is interposed between the first dielectric substrate and the second dielectric substrate without any gap.   3. The antenna device according to claim 1, wherein the dielectric substance B has a dielectric constant greater than a dielectric constant of the dielectric substance A. 4.   4. The antenna device according to claim 1, wherein the dielectric substance A is silicone rubber. 5.   5. The antenna device according to claim 1, wherein the dielectric substance B is titanium oxide particles. 6.   5. The antenna device according to claim 1, wherein the dielectric substance B is alumina particles. 6.   2. The antenna device according to claim 1, wherein the dielectric substance B is air bubbles. 8. The antenna device according to claim 1, wherein the electromagnetic coupling conductor extends from a counter substrate surface of the second dielectric substrate toward the first dielectric substrate. 9. Is provided,
The electromagnetic coupling conductor and the ground conductor are galvanically insulated,
An antenna device, wherein the electromagnetic coupling conductor and the patch conductor are electromagnetically coupled. 8. The antenna device according to claim 1, wherein the first dielectric substrate protrudes from the counter substrate surface of the second dielectric substrate toward the first dielectric substrate. Is provided with a columnar conductor electrically connected as a signal line to the patch conductor provided in
The antenna device according to claim 1, wherein the columnar conductor and the ground conductor are galvanically insulated.   The antenna device according to any one of claims 1 to 9, wherein the first dielectric substrate is made of glass.   11. The antenna device according to claim 1, wherein the first dielectric substrate is an automobile window glass having a curved surface. 11. The method for manufacturing an antenna device according to any one of claims 1 to 8, comprising the following steps (1) to (5).
(1) Prepare a window glass plate that is the first dielectric substrate that is fitted in the opening of the vehicle and provided with the patch conductor;
Alternatively, a window glass plate, which is the first dielectric substrate, is prepared before being fitted into the opening of the vehicle and provided with the patch conductor.
(2) An adhesion part is formed in a window glass plate, or an adhesion part is formed in the window glass plate side surface of the said spacer.
(3) A spacer is attached to a predetermined portion of the window glass plate through the bonding portion.
(4) After the second dielectric substrate is fixed to the spacer, the mixed dielectric material is injected into a gap surrounded by the window glass plate, the second dielectric substrate, and the spacer.
(5) In the above step (1), when the window glass plate before being fitted into the opening of the vehicle is used, the window glass plate is fitted into the opening of the vehicle.   13. The method of manufacturing an antenna device according to claim 12, wherein a molding frame is provided on the second dielectric substrate instead of the step (4), and the mixed dielectric material is caused to flow into the frame. A method for manufacturing an antenna device, comprising: a step of removing the frame and fixing the second dielectric substrate to the spacer after reducing fluidity. 14. The method of manufacturing an antenna device according to claim 12 or 13, wherein the electromagnetic coupling conductor is provided on the second dielectric substrate in the step (4) or a step provided in place of the step (4). Or the columnar conductor is attached, The manufacturing method of the antenna device characterized by the above-mentioned.

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